Due to the fact that aluminum-magnesium alloys have excellent formability, various types have been proposed in the abovementioned technical area, and have been used in prototypes and other products.
For example, JP-A H07-278716 discloses an aluminum alloy sheet for forming, having excellent local elongation, obtained by adding silicon and iron, the allowable amounts thereof being fairly high, to an aluminum-magnesium alloy containing a specific amount of magnesium, and during casting, making the thickness of the casting slabs thin, regulating the solidification rate of the molten alloy, and restricting the size of the intermetallic compounds.
However, in the abovementioned technical area, in recent years, an increasingly high strength is being sought for materials after baking treatment, and an aluminum-magnesium alloy is being sought which has high strength prior to baking treatment, and in addition, has very little decrease in strength after baking treatment is performed, that is, its bake softening ratio is low.